Traversely swinging gun breech with obturating seal



TRAVERSELY SWINGING GUN BREECH WITH OBTURATING SEAL Filed Feb. 1, 1960 2Sheets-Sheet 1 Fig -1- INVENTOR.

Rnheri J 1m;

Sept. 5, 1961 J. THIERRY 2,998,755

TRAVERSELY SWINGING GUN BREIECH WITH OBTURATING SEAL Filed Feb. 1, 19602 Sheets-Sheet 2 INVENTOR. R mhafi I 113w TRAVERSELY SWINGING GUN BREECHWITH OBTURATING SEAL Robert J. Thierry, Averill Park, N.Y., assignor tothe United States of America as represented by the Secretary of the ArmyFiled Feb. 1, 1960, Ser. No. 6,076

6 Claims. (Cl. 89-26) (Granted under Title '35, U.S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment of anyroyalty thereon.

This invention relates to guns having a chamber which is pivotallyseparated from the tube and which is mount ed for such pivotal movementaround an axis which is parallel to the axis of the tube, and theinvention pertains more particularly to means for coupling the chamberand tube when aligned in battery position and for sealing the jointtherebetween.

In large caliber guns, in which the propellant and projectile arehandloaded separately thereinto, and where the gun is mounted so thatspace for such handloading from the rear is limited, it has been foundadvisable to have the chamber separate from the tube by swingingoutwardly from the side therefrom so that the propellant can be loadedrearwardly into the chamber and the projectile inserted forwardly intothe tube.

nited States Patent The available chamber opening and locking designsFIG. 3. 1

when in battery position which are simple and rugged in construction.

In such guns with a pivotal chamber it is, of course, necessary toobturate the joint between the tube and chamber. This requires a sealwhich must be carried either by the tube or chamber and which must makesealing connection therebetween each firing cycle. Therefore, it isnecessary to provide a seal which can be used frequently and for a largenumber of cycles and which is extendable relative to the axis of the gunso as to maintain sealing connection with the chamber and tube duringdilation of the joint therebetween by the discharge forces.

In such firearms, too, the initial closure force which can be applied tothe seal mechanically is limited because of the absence of axialmovement between the tube and chamber. Consequently, the seal must beone which is energized by the pressure of the gases produced by thedischarge of the propellant in the chamber.

The available self-energizing seals for high pressure vessels aremodifications of the Bridgman, delta, lens, wave and 0 types. Theseseals, however, use the unsupported area principle and, therefore, arenot adaptable to firearm use because the unsupported area causes plasticdeformation of the seal to produce a gradual and progressive yieldingwhich increases the dimensions of the seal to the extent that thechamber is prevented from closing after only a few rounds.

In such guns, too, the seal has to be mounted in the face of either thetube or chamber and is biased for resilient contact with the face of theopposite member for initial sealing contact. Therefore, when the chamberis swung to and from the battery position, one of the sealing surfaceswipes along the face of the opposite member to cause deformation andwearing of such sealing portion.

It is, therefore, another object of this invention to provide for suchpivotal chamber guns a ring seal which is fully supported in back of thesealing surfaces to prevent plastic deformation thereof so that the ringseal is usable for many rounds.

It is still another object of this invention to provide a ring sealwhich is received by an annular seat in the front face of the chamberand includes a portion which is biased into resilient contact with therear face of the tube for initial sealing contact with the chamber andtube.

It is a further object of this invention to provide a ring seal which issubstantially M-shaped in cross-section and of a bellows-like structureso as to be expandable to maintain sealing contact with the tube andchamber during dilation of the joint therebetween.

It is another and further object of this invention to provide on theportion of the ring seal that contacts the rear face of the tube duringmovement of the chamber to and from battery position an integral camfollower which maintains the sealing surface on such portion out ofcontact with the rear face of the tube when the ring seal is movedthereacross.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

FIG. 1 is a side view of the gun partially cross-sectioned to show therelation of the seal and coupling when the chamber is in batteryposition;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 2 but showing the chamber in the openposition; and

FIG. 4 is an enlarged view taken along line 44 of Shown in the figuresis a gun 12 having a tube 14 with a bore 16 for receiving a projectile.A chamber 18 is separable from tube 14 and includes a well 20 forreceiving propellant to energize the projectile. Well 20 extendsrearwardly into chamber 18 from a front face 22 thereof. Chamber 18 isswung outwardly away from tube 14 for opening the rear end of bore 16and the mouth of Well 20 to permit the loading of gun 12. by a motor24-. Motor 24 may be energized by electric, hydraulic or recoil-poweredmeans, whichever is themost practical, and includes a housing 26 whichis connected by a bracket 28 to tube 14. Motor 24, as shown in FIG. 1,includes a rotor 30 which is disposed so that the longitudinal axisthereof, noted at x-x, is parallel to axis OO of tube 14 and which isrotated when the motor is energized. Chamber 18 is connected by abracket 31 to a hub 32 which is coaxially mounted on rotor 30 for rotarymovement respective thereto so that the chamber is pivotally supportedby such rotor. Hub 32 is con nected to rotor 30 by a torsion bar 34,whereby chamber 18 is pivotable by motor '24 between an open loadingposition and a closed battery position and is resiliently held in eitherone of the two positions by continued limited rotation of the motor,after the chamber is stopped therein, so as to energize torsion bar 34.A latching device (not shown) may be provided to releasably lock chamber18 in either position if found desirable.

A coupling device 36 connects chamber 18 to tube 14 when the chamber isin battery position to prevent free axial movement therebetween and tosupport the joint where the chamber and tube contact to minimize thedilation of the joint by discharge forces. Coupling de vice 36, as bestshown in FIG. 4, includes a peripheral flange 40 which extends aroundthe front end of chamber 18 and a collar 42 which is provided withinternal threads for engaging a threaded portion 38 which extendsforwardly along tube 14 from a rear face 44 thereof. Flange 40 andcollar 42 are releasably locked together by a conpler 46 anchored totube 14 and a secondary-coupler 48 anchored to chamber 18. Coupler 46 istubular in cpn' figuration and is provided with an annular channel 50around the inside thereof. Channel 50 forms a rearward lip 52 and aforward mounting portion 54 which is provided with internal threadswhich engage threaded portion 38. In installation, coupler 46 would bemounted on tube 14 first and then collar 42 installed afterwards withthe collar and mounting portion 54 being in contact when finallyassembled and the collar located adjacent rear face 44.

The diameter of channel 50 is similar to the outside diameter of flange40 so that the flange is receivable therein and the width of the channelis such that lip 52 is spaced sufliciently rearward of rear face 44 oftube 14 to form therebetween a clearance 56 which matingly receivesflange 40 when chamber 18 is in battery position. Channel 50 and lip 52are interrupted by an opening 58 (FIG. 3) through coupler 46 to permitthe passage of chamber 13 therethrough to battery position.

Secondary-coupler 48 includes a circular mounting section 60 whichthreadingly engages chamber 183and which is mounted thereon to contactthe rear end of flange 40. A segmental portion 62 extends forwardly frommounting section 60 and such segmental portion has a configurationsimilar to opening 58 so as to be receivable therein to complete thetubular configuration of coupler 46. Segmental portion 62 is arcuatelyrecessed to complete channel 50 and such recess forms a lip 64 which isreceivable by a mating recess 66 formed in the rear of mounting portion54 so that such lip is in contact with the front surface of collar 42when chamber 18 is in battery position. Another recess 67 is formed inmounting section 60 of secondary-coupler 48 to matingly receive lip 52and permit contact thereof with the rear end of flange 4f}. Whereby,when chamber 18 is in battery position, flange 40, collar 42 and thelips 52 and 64 are interlocked to prevent free axial displacementbetween tube 14 and chamber 18 and the joint therebetween is supportedcompletely therearound.

Chamber 18 is counterbored from front face 22 to form a seat 63 at themouth of well 20 for receiving a ring seal 70 which obturates the jointbetween the chamber and tube 14. Seat 68 includes an annular end wall 71and a circular outer wall 72. Ring seal 70 is retained in seat 68 bypressing a retainer ring 74 between the ring seal and outer wall 72.Ring seal 70 in crosssection is essentially M-shaped in configurationwith the inside opening to the inside of chamber 18 so as to besubjectable to the pressure of discharge gases therein. Ring seal 70includes a rear section 76 having contact with end wall 71, a base 78which contacts retainer ring 74 and which is crimped inwardly to form aU-shaped projection 80 for a bellowslike structure, and a front section82 which is contactable with rear face 44 of tube 14. The leading edgesof rear section 76 and front section 82 are pressed slightly apart sothat ring seal 70 makes sealing contact with end wall 72 at a sealingsurface 83 which extends around the rear section 76 adjacent the edgethereof and with rear face 44 of tube 14 at a sealing surface 84 whichextends around front section 82 adjacent the edge thereof.

Sealing surface 84 is positioned, normally, forwardly of front face 22so that when chamber 13 is rotated to battery position and front section82 is slidingly engaged by rear face 44, ring seal 70 is compressed andthereby preloaded to assure initial obturation. It is obvious thatsealing surface 84 would be severely mutilated if permitted to contactrear face 44 when chamber 18 is swung to and from battery position.Therefore, front section 82 is provided with an integral cam follower 86which projects outwardly beyond sealing surface 32 between the sealingsurface and base 78 and extends around such front section. Whcreby, whenchamber 18 is rotated to and from battery position, the contact betweencam follower 86 and rear face 44 holds sealing surface 84 out of contacttherewith. Rear face 44 is provided with a radius at the outsideperiphery thereof to form a cam surface 88 for easing cam follower 86onto the rear face when chamber 18 is initially moved from openposition. When chamber 18 is in battery position, cam follower 86 isreceived by an annular groove 90 formed in rear face 44 to permitcontact between sealing surface 84andlthe rear face.

From the foregoing it isclearly-apparent that there is provided herein aself-energizing seal "wherein the sealing surfaces 83 and 84 are fullybacked by end wall '72 and rear face 44, respectively, so that ring seal70 is not plastically deformed by the pressure of the discharge gasesand that, through the bellowslike configuration of the ring seal,sealing contact is maintained withtube 14 and chamber 18 during thedilation of-the jointtherebetween resulting from discharge forces. It isalso clearly apparent that the efficiency of ring seal 70 is prolongedconsiderably by sealing surface 84 being held away from contact withrear face 44 during movement thereover.

It is also evident that the means for actuating chamber 1% between theloading and battery positions and for coupling it with tube 14 aresimple and rugged in construction.

While the preferred embodiment shows the invention applied to a gun witha separable chamber, it is evident that the invention may also beeffectively applied to guns, such as mortars, wherein the tube ispivotally dividable into two coextensive sections so that the frontsection may be pivoted to the side to permit the loading of he mortarshells from the front end of the resulting shortened length of the tube.I

Although a particular embodiment of the invention has been described indetail herein, it is evident that many variations may be devised withinthe spirit and scope thereof and the following claims are intended toinclude such variations.

I claim:

1. In a gun having a tube member, a chamber member mounted to said tubemember for pivotal displacement between an open loading position and aclosed battery position, an axially flexible ring seal carried by saidchamber member for forming a gas-tight seal between said tube andchamber member when said chamber member is in the battery position, asealing surface disposed on said ring seal for sealing contact with saidtube member when said chamber member is in the battery position,cooperating cam means disposed on said ring seal and said tube memberfor compressing said ring seal to displace said sealing surface clear ofcontact with said tube member during pivotal displacement of saidchamber member to and from the closed position, and means to permitforward expansion of said ring seal when said chamber member is in thebattery position and thereby obtain sealing contact between said sealingsurface and said tube member.

2. In a gun having a tube member, a motor provided with a rotor and ahousing mounted on the tube member, a chamber member supported by saidrotor for pi votal displacement thereby between an open loading positionand a closed battery position, a torsion bar operationally disposedbetween said rotor and said chamber member so as to be energizable bysaid motor for resiliently holding said chamber member in the batteryposition after said chamber member is displaced by said motor thereto, acoupling device for joining said chamber member to said tube member whenin the battery position, an axially flexible ring seal carried by saidchamber member for forming a gas-tight seal between said chamber andtube member when said chamber member is in the battery position, asealing surface disposed on said ring seal for sealing contact with saidtube member when said chamber member "is in the battery position,cooperating cam means disposed on said ring seal and said tube-memberfor compressing said ring seal to hold said sealing surface clear ofcontact with said tube member during pivotal displacement of saidchamber member to and from the battery position, and means forpermitting forward expansion of said ring seal when said chamber memberis in the battery position to obtain sealing contact between saidsealing surface and said tube member.

3. The gun as defined in claim 2 wherein said tube member is providedwith a rear face and an outside pen'phery, said cam means includes a camfollower disposed around said ring seal adjacent said sealing surfaceand so as to extend forwardly thereof and a cam surface in said tubemember leading rearwardly from the periphery thereof to said rear face,said cam surface be ing disposed for contact by said cam follower duringdisplacement of said chamber member to the closed position forcompressing said ring seal and delivering said cam follower into slidingcontact with said rear face, and said means to permit release of saidring seal comprising an annular groove disposed in said rear face formatingly receiving said cam follower when said chamber member is in thebattery position.

4. The gun as defined in claim 2 wherein said ring seal is ofbellowslike structure and said chamber member is provided with a seatformed for receiving said ring seal so that the inside thereof is opento gas pressure in said chamber member and so that the front end of saidring seal extends forwardly from said chamber member to make resilientcontact with said tube member when said chamber member is in the batteryposition.

5. The gun as defined in claim 2 wherein said chamber member is providedwith a propellant receiving well which extends rearwardly thereinto andwhich is counterbored at the entrance to form for said ring seal a seathaving an annular end wall and an outer wall, and wherein said ring sealis of expandable bellowslike structure energizable by the pressure ofgases in said chamber member, said ring seal including a rear sectionwhich has sealing contact with said end wall and is supported therebywhen said ring seal is energized, a front section which is contactablewith the rear end of said tube member and is supported thereby when saidring seal is energized and which is disposed to be pressed rearwardly bythe rear end of said tube member when passing thereover to preload saidring seal for initial obturation when said chamber member is in batteryposition, a base which integrally joins said front and rear sections sothat said ring seal is open to the gases in said chamber member, and anintegral U-portion crimped inwardly around said base for accommodatingsaid ring seal to relative axial movement between said tube member andchamber member without plastic deformation.

6. The gun as defined in claim 2 wherein said coupling device includes aperipheral flange at the front end of said chamber member, a collarthreadably mounted on said tube at the rear end thereof, a tubularprimary coupler having a mountingportion for-anchoring said coupler tosaid tube, a lip disposed rearwardly of the rear end of said tube memberfor contact with the rear end of said collar when said chamber member isin battery position and a channel disposed between said mounting portionand lip to matingly receive said flange, an opening in said primarycoupler interrupting said channel and lip to permit passage of saidchamber member to battery position, a secondary coupler anchored to saidchamber member by means of an encircling mounting section having contactwith the rear end of said flange, a segmental portion extendingintegrally forward from said mounting section, said segmental portionhaving the same configuration as said opening to complete the outsidetubular configuration of said primary coupler and said channel and liptherein, a recess formed in said mounting section to permit contact ofsaid lip with the rear end of said flange when said chamber member is inbattery position, and a lip disposed on the inside of the front end ofsaid segmental portion so as to be receivable by a recess in saidmounting portion of said primary coupler for contact with the front endof said collar.

References Cited in the file of this patent UNITED STATES PATENTS1,072,319 Dawson et al. Sept. 2, 1913 1,394,490 Giles Oct. 18, 19212,468,134 Swipp Apr. 26, 1949 2,790,353 Bird Apr. 30, 1957

